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(No Model.) 2 Sheets-Sheet 1. C. A. FREDERICKS.

GRINDING MILL. 'No. 282,068. Patented July 31, 1883.

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Z-Sheets-Sheet 2 (No Model.)

0. A. PREDERICKS. GRINDING MILL.

No. 282,068. Patented July 31; 1883. I

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UNITED STATES PATENT OFFICE.

' CHRISTIAN A. FREDERIOKS, on BROOKLYN, NEW YORK.

GRINDING-MILL.

' iSPECIFICATION forming'part of Letters Patent No. 282,068, dated July 31, 1883..

TOTO/Z2 whom/ it may concern:

3 Be it' known that I, CHRISTIAN A. FRED- ug-Mills, of which the following is a specifi E'RIOKs, a citizen of the United. States, and a resident of Brooklyn, Kings county, New York,-

have invented certain Improvements in Grindnarily constructed,'-with less expensive construction and less liability to get out of order. In the drawings, which serve to illustrate my invention, Figure 1 is a vertical mid-sec tion of a mill provided with my improvements,

the section being taken in the plane of the axis; of rotation. of the grinder. Fig.2 is a sideelevation of the casing of the mill, the hopper andbase being broken away. Fig. 3 is a front elevation of the fixed or non-rotating grinding face or plate. Fig. 4 is a front elevation, and Fig. 5 is a side elevation, of the rotary grinder. Fig. 6 is a modification of the means for adjusting the rotary grinder.

A represents the ordinary hopper for the substance to be ground; 13, the base of the mill, containing a drawer, (l, to receive the ground substance; D, the shaft, and E E the fly and crank wheels fixed thereon. These are all, generally speaking, constructed in the usual way. I

The casing or shell which contains the grinding mechanism, may be of anydesired form. I have herein shown it as globulaix It is composed of two parts, F and F, the latter being a removable cap. The part F comprises the shell portion a, wherein is formed the outer bearing, b, of the shaft, the fixed grinding-face I 0, provided with the depressed eye or recess A c, which furnishes the inner hearing, I), of

the shaft, and the chute d, which leads the substance to be ground from the hopper to the recess or eye 0. These are all cast in one piece, by preference, with suitable attaching-flanges, e 6. By this means I insure the greatest rigidity and firmness of the fixed grinding-face and its correct setting at right angles with the shaft.

Applicationfilcd April .26, 1883. (No model.)

The two bearings b b being fixed with refer ence to face 0, it is only necessary to see that these hearings are bored properly to be sure that the grinders shall always be properly presented to each other, face to face. The cap F is made to fit up to and take over the part F- that is, to say, at its upper end (see Fig. 1) it takes under the flange e 011 F, while at its bottom or lower'end it rests on the top of C. At its sides (see Fig. 2) it is provided with a shouldered flange,- c, which takes over the adjacent edge of F. It is secured to F by means of two screws 9, one on each side. This cap F is bored to form a third bearing, N, for the shaft after it is fitted and secured to F, which insures the proper alignment of the three bearings at all times whenever the cap is removed and replaced.

G is the rotary grinder, which is mounted fixedly, but removably, on the shaft D by means of a set-screw, f, or other equivalent means.

In F is provided, as before stated, a third bearing, I)", for the shaft D, and .in it is also formed a socket, 71 internally screw-threaded to receive a brush or gland, H, which screws down against a fixed collar, 13, on the shaft D. This enables me to adjust the rotary grinder G up to the fixed grinding-face 0, so as to grind coarse or fine, as desired. It will readily be seen that any pressure exerted on the collar i by the gland II will move the shaft ,endwise (to the right in Fig. 1) and carry the grinder G with it.

I will now describe the peculiar construction of the grindinglaces with reference particularly to Figs. 3, 4., and 5.

In some mills the grindingfaces consist, substantially, of small pyramidal projections arranged in concentric circles, the circle on one face taking into the space between the adjacent circles on the other face. These mills. rely on breaking and crushing, the substanoe coffee, for eXample--and when worn or dull they cannot be made to grind finely and evenly. I seek toproduce grinding-faces which will practically never become dull, even when worn down very materially, that will not break or crush the coffee except at the first, as will be explained, but will shear or scrape it off in fine particles or shavings, and that will gradually feed it as it is being cut away to the skirt or periphery or discharging-point of the grinder. Referring then to the fixed grinder shown in Fig. 3, j j are cutting or breaking ribs formed in the eye or recess 0, and k is a coned projection, Figs. 4 and 5, on the rotary grinder G, which takes into recess 0, and is provided with ribs k, opposed to those inrecess 0. Between these the coffee is broken into bits, and it passes thence out to the vertical grindingfaces. The grinding-face c has numerous radial V-shaped leading furrows, l, which are quite deep where they start from the margin of the recess 0, but run out to nothing at m. As these furrows diverge and separate widely at their ends, I provide branch furrows n of the same character, which project obliquely from the leading furrows Z. These serve to break up the otherwise smooth face of the grinder between the furrows. The furrows Z and a are simply designed to hold the bits of coffee or other substance. The cutting or shearing is done by the rotary grinder, which I will. now more minutely describe with reference to Figs. 4 and 5. The face of this grinder is divided up into furrows 0, which are oblique to the radius and preferably curved. These furrows, as indicated in Fig. 1, have a perpendicular side or face and a slightly-inclined face, thus dividing up the face of the grinder into perpendicular offsets and slightly-inclined faces 5 but these furrows 0, like the furrows in the fixed grinding-face, are deepest near the center of the grinderthat is, at the base of k-andbccome shallower and narrower toward the skirt or periphery, the triangular portions p representing the level. normal face of the grinder, and the shallow outlets for the ground coffee or other substance. The grinder G rotates in the direction of the arrow in Fig. 4, and thus the obliquity of the furrows causes them to move outward with a shear or draw cut over the bits of coffee held in the furrows in the fixed grinder, and to feed the substance toward the outlets q and exp'el it therefrom at the same time that it shears off the top of each bit. These grooves 0 cut with their ab rupt or vertical surfaces.

I usually make the fixed grinder c of ordinary cast-iron and the rotary grinder G of chilled iron. As the latter wears away in use the perpendicular edges of its furrows still remain sharp. They may be, indeed, slightly undercut instead of perpendicular.

The gland. H enables me to readily adjust the mill as to fineness and coarseness of grind ing; and to prevent the accidental disarrangement of the adjustment a set-screw, 1', may be employed. Should any hard foreign substance get into the mill by accident, the gland H may be removed or partially unscrewed, and this will permit the rotary grinder to be drawn back from 0 far enough to permit such substance to fall into the receiver below without the necessity of taking the mill to pieces. Or the cap F may be detached by simply removing the two screws y, when the same result will be attained. This may be done by any one without disarranging the mill, and it requires no special skill. In Fig. 6 I have shown amodification of this adjusting device, in which the boss of the grinder G is prolonged to extend out through the cap F, whereby the collar '13 is rendered unnecessary; and in lieu of the gland H, aforked lever, H, is mounted on the cap F, and its forked end made to straddle shaft D and impinge on the end of the boss, (here lettered 2".) A screw, 8, serves to effect the adjustment. I might, however, use the collar 1' in this construction, and I might substitute the prolonged boss i in the construction shown in Fig. 1. \Vhere a prolonged boss, 1', is employed, I might also spline the grinder G on the shaft and omit the screw 1. I11 that case the grinder only would be moved in adjusting, and not-the shaft.

In order to get at the interior of the casing it is only necessary to remove the two screws 9 at the sides, one of which is shown in Fig. 2. By removing the right-hand wheel E the shaft, with the grinder G, may be entirely removed.

It will sometimes happen that a stone or other hard substance will enter the mill, and in mills as ordinarily constructed this is apt to break the wall of the recess 0.

with the chute d and grinding-face c, where by it is made rigid and very strong. The shell a might be made separately from the for the purpose of increasing the strength and having the bearings 11 and b in one piece, I prefer the construction shown.

It is not absolutely necessary that the furrows 1 and a be V-shaped in section. They might, for example, be flutes; but I prefer the construction shown but in any case these furrows are not designed to have vertical cutting-edges. V

In Fig. 1 tis the passage for the ground substance from the mill to drawer O.

I have said that I prefer to make the oblique furrows in the grinder G curved,'and I will add that I prefer for this purpose that form known as the caustic curve as being the best suited to my purpose.

claim- 1. In a grinding-mill, the grinding-face 0, provided with an eye or recess, 0, having ribs j j, and with radial furrows Z, made deepest at the center and running out at an, in combination with the rotary grinder G, provided with rows 0, made deepest at the center of the grinder, and terminating at the skirt in the lesser dischargeoutlets q, substantially as and for the purposes set forth.

2. A mill for grinding coffee and for other analogous purposes, provided with a fixed To avoid this I make this wall thick and cast it in one other parts of F and be screwed thereto; but,-

Having' thus described my invention,

i a cone, k, having ribs 70, and with oblique furing 1), and the flange e, the cap F, provided with abearing, b and a flange, a, and arranged 15 to fitbetween flange 6 and base B, the said base, the shaft, andthe rotary grinder all constructed substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of two subscribing 20 witnesses.

CHRISTIAN A. FREDERICKS.

Witnesses:

HENRY CONNETT, ARTHUR O. FRASER. 

